Piston Coffee Machine Hold-to-Operate Mechanism for Lever Safety
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Solution Overview
Problem
Piston-type coffee machines pose safety risks due to the rigid connection between the operating lever and raising arm, requiring high lever force for dispensing, fixed pressure profiles, and wear on sealing rings from the water filling mechanism.
Innovation Solution
A coffee machine with a 'hold-to-operate' mechanism connecting the operating lever and eccentric member only through voluntary action, allowing adjustable spring compression and water introduction above the piston, reducing the risk of sudden lever movement and enabling variable pressure profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the operating lever and raising arm are rigidly connected, then the machine can dispense coffee with high pressure, but the lever may slip and be pushed violently upwards causing safety risks
Solution Approach 1:
The patent divides the rigid connection into two separate components: the operating lever and the raising arm. These are connected through a coupling mechanism that allows relative movement, enabling the system to maintain high dispensing pressure while preventing violent lever movement if the operator releases the lever.
Solution Approach 2:
The patent introduces a coupling mechanism as an intermediary between the operating lever and the raising arm. This intermediary component transmits the operating force while allowing controlled movement, thereby maintaining pressure generation capability while eliminating the safety hazard of violent lever rebound.
2Device complexity
If the spring preload is fixed, then the machine structure is simple, but the pressure profile cannot be adjusted
Solution Approach 1:
The patent transforms the fixed spring preload system into a dynamic, adjustable system. The spring preload can be modified by changing the position of the stop or by using interchangeable springs, allowing the operator to adjust the pressure profile according to different brewing requirements while maintaining relatively simple mechanical structure.
3Device complexity
If water is introduced only when the piston is in the upper position, then the sealing is simplified, but the operator cannot obtain dispensing with medium-to-low pressure
Solution Approach 1:
The patent makes the water introduction timing dynamic rather than fixed. The water inlet valve is controlled to open at different positions during the piston stroke, allowing water to be introduced at various points. This enables the operator to achieve medium-to-low pressure dispensing by introducing water earlier in the stroke while maintaining simple sealing arrangement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances safety by preventing sudden lever movements, reduces the force required for operation, allows adjustable pressure settings, and minimizes wear on sealing rings by introducing water above the piston, resulting in a more user-friendly and versatile brewing experience.
Implementation Method 1
a spring (3) which is configured to be compressed by said operating lever when said piston (2) moves from said first position to said second position and to push said piston from said second position to said first position
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
A machine (100) for espresso coffee (barley or other beverages) of the piston type is described. The machine comprises a cylinder (1), a piston (2) which is configured to perform a translation movement in said cylinder (1), a rod (4) having an end cooperating with said piston (2), an operating lever (5), a member (6) configured to cooperate with said rod (4) and to move said piston (2) from a first position to a second position by compressing a spring (3), and a mechanism (8, 10, 11, 12) which realizes the connection between said operating lever (5) and said member (6), wherein said mechanism is of the "hold-to-operate" type.